YouTube's enormous popularity has created a big headache for another "utube"--a company that sells used machines that make tubes. Universal Tube & Rollform Equipment's Web site, <A HREF="http://news.yahoo.com/s/ap/20061013/ap_on_hi_te/youtube_vs__utube;_ylt=AixZbYCJXX_ouD6t3TLRuWas0NUE;_ylu=X3oDMTA3cjE0b2MwBHNlYwM3Mzg-">utube.com, was inaccessible for most of the week,</A> overwhelmed by millions of people looking for the popular online video site. The confusion took off a couple of months ago, said Ralph Girkins, Universal Tube's president.